The present invention relates to agents for oxidatively dyeing keratin fibers, especially human hair, on the basis of a combination of a developer and coupler, which contains N-benzyl-p-phenylenediamine derivatives as developer, as well as to new N-benzyl-p-phenylenediamine derivatives.
In the field of dyeing keratin fibers, especially of dyeing hair, oxidation dyes have achieved considerable importance. The dyeing results here from the reaction of certain developers with couplers in the presence of a suitable oxidizing agent. As developers, especially 2,5-diaminotoluene, 2,5-diaminophenylethyl alcohol, p-aminophenol and 1,4-diaminobenzene are used here, while as couplers, resorcinol, 4-chlororesorcinol, 1-naphthol, 3-aminophenol and derivatives of m-phenylenediamine, for example, are named.
Oxidation dyes, which are used for dyeing human hair, must satisfy numerous requirements, in addition to dyeing in the desired intensity. For example, the dyes must be safe from a toxicological and dermatological point of view and the hair dyeings achieved must have good light fastness, permanent waving fastness, acid resistance and crocking fastness. In any case, such dyeings must remain stable for a period of at least 4 to 6 weeks without the action of light, rubbing and chemical agents. In addition, it is necessary that a broad range of different color nuances can be produced by combining suitable developers and couplers.
From the German Offenlegungsschrift 34 32 214, agents, which contain a particular N-benzyl-p-phenylenediamine, such as N-benzyl-p-phenylenediamine, N4-benzyl-1,4-diamino-2-methylbenzene and 2-(((4-aminophenyl)amino)methyl)-4,6-dichloro-phenol, are already known for dyeing hair. However, these compounds do not fulfill the requirements, which must be met by dyes for oxidation dyes, in every respect. There is therefore a continuing need for further, suitable, new dyes.
It has now been found that, if N-benzyl-p-phenylenediamine derivatives of the general Formula (I) are used, intensive brown, blue and red color nuances are obtained.
The object of the present invention therefore is an agent for oxidatively dyeing keratin fibers, such as wool, fur, feathers or hair, especially human hair, on the basis of a combination of developer and coupler, which contains, as developer, at least one N-benzyl-p-phenylenediamine derivative of Formula (I), 
in which
R1 R1 is hydrogen, a (C1-C4) alkyl group or a hydroxy-(C1-C4) alkyl group,
R2 is hydrogen, a halogen atom (F, Cl, Br, I), a cyano group, a (C1-C4) alkoxy group, a hydroxy (C1-C4) alkoxy group, a (C1-C6) alkyl group, a (C1-C4) alkyl thioether group, a mercapto group, a nitro group, an amino group, a (C1-C4) alkylamino group, a di-(C1-C4) alkylamino group, a di-(hydroxy-(C1-C4)-alkyl) amino group, a (hydroxy-(C1-C4)-alkyl) amino group, a trifluoromethane group, a xe2x80x94C(O)CH3 group, a xe2x80x94C(O)CF3 group, an xe2x80x94Si(CH3)3 group, a hydroxy-(C1-C4) alkyl group, a dihydroxy-(C3-C4) alkyl group or a morpholino group
R3, R4 independently of one another are hydrogen, a halogen atom, a hydroxy group, a (C1-C4) alkoxy group, a hydroxy-(C1-C4) alkoxy group, a (C1-C6) alkyl group, a (C1-C4) alkyl thioether group, a mercapto group, an amino group, a (C1-C6) alkylamino group, a di-(C1-C6) alkylamino group, a di-(hydroxy-(C1-C4)-alkylamino group, a hydroxy-(C1-C4) alkylamino group, a trifluoromethane group, an acetamido group, a xe2x80x94C(O)CH3 group, a xe2x80x94C(O)CF3 group, an xe2x80x94Si(CH3)3 group, a hydroxy-(C1-C4) alkyl group or a dihydroxy-(C3-C4) alkyl group or R3 and R4 together form an xe2x80x94Oxe2x80x94CH2xe2x80x94Oxe2x80x94 bridge and
R5 is hydrogen, a hydroxy group or a (C1-C6) alkyl group,
with the proviso that
(i) at least one of the R2 to R5 groups is different from a hydrogen and
(ii) R1 is not hydrogen or a (C1-C4) alkyl group when R2=R4=R5=hydrogen and R3=chlorine.
The following, for example, can be mentioned as examples of compounds of Formula (I): N-((2-aminophenyl)methyl)-1,4-diaminobenzene, N-((3-aminophenyl)-methyl)-1,4-diaminobenzene, N-((3-hydroxyphenyl)methyl)-1,4-diaminobenzene, N-((4-aminophenyl)methyl)-1,4-diaminobenzene, N-((4-hydroxyphenyl)methyl)-1,4-diaminobenzene, N-((2-(1-hydroxyethoxy)-phenyl)-methyl)-1,4-diaminobenzene, N-((2-methoxyphenyl)methyl)-1,4-diaminobenzene, N-((3-(1-hydroxyethoxy)-phenyl)methyl)-1,4diaminobezene, N-((3-methoxyphenyl)methyl)-1,4-diaminobenzene, N-((4-hydroxy-3,5-dimethyl-phenyl)methyl)-1,4-diaminobenzene, N-((4-(1-hydroxyethoxy)-phenyl)methyl)-1,4-diaminobenzene, N-((4-methoxyphenyl)methyl)-1,4-diaminobenzene, N-((2-(2-hydroxyethylamino)-phenyl)methyl)-1,4-diaminobenzene, N-((2-(bis-(2-hydroxyethyl)amino)-phenyl)methyl)-1,4-diaminobenzene, N-((2-dimethylamino-phenyl)methyl)-1,4-diaminobenzene, N-((2-pyrrolidino-phenyl)methyl)-1,4-diaminobenzene, N-((3-(2-hydroxyethylamino)-phenyl)methyl)-1,4-diaminobenzene, N-((3-(bis-(2-hydroxyethyl)amino)-phenyl)methyl)-1,4-diaminobenzene, N-((3-dimethylaminophenyl)methyl)-1,4-diaminobenzene, N-((3-pyrrolidino-phenyl)methyl)-1,4-diaminobenzene, N-((4-(2-hydroxyethylamino)-phenyl)methyl)-1,4-diaminobenzene, N-((4-(bis-(2-hydroxyethyl)amino)-phenyl)methyl)-1,4-diaminobenzene, N-((4-dimethylamino-phenyl)methyl)-1,4-diaminobenzene, N-((4-pyrrolidino-phenyl)methyl)-1,4-diaminobenzene, N-benzo[1,3]dioxol-5-ylmethyl-1,4-diaminobenzene, N-benzo[1,3]dioxol-6-ylmethyl-1,4-diaminobenzene, N-{2-[(4-amino-phenylamino)-methyl]-phenyl}-acetamide, N-{3-[(4-amino-phenylamino)-methyl]-phenyl}-acetamide, N-{4-[(4-amino-phenylamino)-methyl]-phenyl}-acetamide, N-((2,3-diaminophenyl)methyl)-1,4-diaminobenzene, N-((2,3-dihydroxyphenyl)methyl)-1,4-diaminobenzene, N-((2,4-diaminophenyl)methyl)-1,4-diaminobenzene, N-((2,4-dihydroxyphenyl)methyl)-1,4-diaminobenzene, N-((2,5-diaminophenyl)methyl)-1,4-diaminobenzene, N-((2,5-dihydroxyphenyl)methyl)-1,4-diaminobenzene, N-((2,6-diaminophenyl)methyl)-1,4-diaminobenzene, N-((2,6-dihydroxyphenyl)methyl)-1,4-diaminobenzene, N-((2-hydroxy-3-aminophenyl)methyl)-1,4-diaminobenzene, N-((2-hydroxy-4-aminophenyl)methyl)-1,4-diaminobenzene, N-((2-hydroxy-5-aminophenyl)methyl)-1,4-diaminobenzene, N-((3-hydroxy-4-aminophenyl)methyl)-1,4-diaminobenzene, N-((3-hydroxy-5-aminophenyl)methyl)-1,4-diaminobenzene, N-((2-amino-3-hydroxyphenyl)methyl)-1,4-diaminobenzene, N-((2-amino-4-hydroxyphenyl)methyl)-1,4-diaminobenzene, N1-((2-aminophenyl)methyl)-2-(2-hydroxyethyl)-1,4-diaminobenzene, N1-((2-aminophenyl)methyl)-2-methyl-1,4-diaminobenzene, N1-((3-aminophenyl)methyl)-2-(2-hydroxyethyl)-1,4-diaminobenzene, N1-((3-aminophenyl)methyl)-2-methyl-1,4-diaminobenzene, N1-((3-hydroxyphenyl)methyl)-2-(2-hydroxyethyl)-1,4-diaminobenzene, N1-((3-hydroxyphenyl)methyl)-2-methyl-1,4-diaminobenzene, N1-((4-aminophenyl)methyl)-2-(2-hydroxyethyl)-1,4-diaminobenzene, N1-((4-aminophenyl)methyl)-2-methyl-1,4-diaminobenzene, N1-((4-hydroxyphenyl)methyl)-2-(2-hydroxyethyl)-1,4-diaminobenzene, N1-((4-hydroxyphenyl)methyl)-2-methyl-1,4-diaminobenzene, N4-((2-aminophenyl)methyl)-2-(2-hydroxyethyl)-1,4-diaminobenzene, N4-((2-aminophenyl)methyl)-2-methyl-1,4-diaminobenzene, N4-((3-aminophenyl)methyl)-2-(2-hydroxyethyl)-1,4-diaminobenzene, N4-((3-aminophenyl)methyl)-2-methyl-1,4-diaminobenzene, N4-((3-hydroxyphenyl)methyl)-2-(2-hydroxyethyl)-1,4-diaminobenzene, N4-((3-hydroxyphenyl)methyl)-2-methyl-1,4-diaminobenzene, N4-((4-aminophenyl)methyl)-2-(2-hydroxyethyl)-1,4-diaminobenzene, N4-((4-aminophenyl)methyl)-2-methyl-1,4-diaminobenzene, N4-((4-hydroxyphenyl)methyl)-2-(2-hydroxyethyl)-1,4-diaminobenzene, N4-((4-hydroxyphenyl)methyl)-2-methyl-1,4-diaminobenzene.
Compounds of Formula (I) are preferred in which
(i) R1 and one of the groups R2 to R5 is hydrogen and/or
(ii) three of the R1 to R5 groups are hydrogen and the two remaining groups, independently of one another, represent hydrogen, a methoxy group, a hydroxy group or an amino group or, in the case of R3 and R4, jointly form an xe2x80x94Oxe2x80x94CH2xe2x80x94O bridge, in which case R2 is not a hydroxy group and at least one of the R2 to R5 groups is not hydrogen.
The following N-benzyl-p-phenylenediamine derivatives of Formula (I) are particularly preferred: N-((3-hydroxyphenyl)methyl)-1,4-diaminobenzene; N-((4-aminophenyl)methyl)-1,4-diaminobenzene; N-((4-hydroxyphenyl)-methyl)-1,4-diaminobenzene; N-((2-methoxyphenyl)methyl)-1,4-diaminobenzene; N-((4-hydroxy-3,5-dimethyl-phenyl)methyl)-1,4-diaminobenzene; N-((4-(2-hydroxyethoxy)-phenyl)methyl)-1,4-diaminobenzene; N-benzo[1,3]dioxol-5-ylmethyl-1,4-diaminobenzene; N-{4-[(4-aminophenylamino)-methyl]-phenyl}-acetamide and N-((4-methoxyphenyl)-methyl)-1,4-diaminobenzene, as well as their physiologically compatible salts.
The compounds of Formula (I) can be used as free bases, as well as in the form of their physiologically compatible salts with inorganic or organic acids, such as hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, propionic acid, lactic acid or citric acid.
The N-benzyl-p-phenylenediamine derivatives of Formula (I) are contained in the inventive dyes in a total amount of about 0.005 to 20 percent by weight, amount of about 0.01 to 5 percent by weight and, in particular, of 0.1 to 2.5 percent by weight being preferred.
As coupler substances, preferably 2,6-diaminopyridine, 2-amino-4-[(2-hydroxyethyl)amino]-anisole, 2,4-diamino-1-fluoro-5-methylbenzene, 2,4-diamino-1-methoxy-5-methylbenzene, 2,4-diamino-1-ethoxy-5-methylbenzene, 2,4-diamino-1-(2-hydroxyethoxy)-5-methylbenzene, 2,4-di[(2-hydroxyethyl)amino]-1,5-dimethoxybenzene, 2,3-diamino-6-methoxy-pyridine, 3-amino-6-methoxy-2-(methylamino)-pyridine, 2,6-diamino-3,5-dimethoxy-pyridine, 3,5-diamino-2,6-dimethoxy-pyridine, 1,3-diaminobenzene, 2,4-diamino-1-(2-hydroxyethoxy)-benzene, 2,4-diamino-1,5-di(2-hydroxyethoxy)-benzene, 1-(2-aminoethoxy)-2,4-diaminobenzene, 2-amino-1-(2-hydroxyethoxy)-4-methylaminobenzene, 2,4-diaminophenoxyacetic acid, 3-[di(2-hydroxyethyl)amino]-aniline, 4-amino-2-di[(2-hydroxyethyl)amino]-1-ethoxybenzene, 5-methyl-2-(1-methylethyl)-phenol, 3-[(2-hydroxyethyl)amino]-aniline, 3-[(2-aminoethyl)-amino]-aniline, 1,3-di(2,4-diaminophenoxy)-propane, di(2,4-diaminophenoxy)-methane, 1,3-diamino-2,4-dimethoxybenzene, 2,6-bis(2-hydroxyethyl)amino toluene, 4-hydroxyindole, 3-dimethylaminophenol, 3-diethylaminophenol, 5-amino-2-methylphenol, 5-amino-4-fluoro-2-methylphenol, 5-amino-4-methoxy-2-methylphenol, 5-amino-4-ethoxy-2-methylphenol, 3-amino-2,4-dichlorophenol, 5-amino-2,4-dichlorophenol, 3-amino-2-methylphenol, 3-amino-2-chloro-6-methylphenol, 3-aminophenol, 2-[(3-hydroxyphenyl)amino]-acetamide, 5-[(2-hydroxyethyl)amino]-2-methylphenol, 3-[(2-hydroxyethyl)amino]-phenol, 3-[(2-methoxyethyl)-amino]-phenol, 5-amino-2-ethylphenol, 2-(4-amino-2-hydroxyphenoxy)-ethanol, 5-[(3-hydroxypropyl)amino]-2-methylphenol, 3-[(2,3-dihydroxypropyl)amino]-2-methylphenol, 3-[(2-hydroxyethyl)amino]-2-methylphenol, 2-amino-3-hydroxy-pyridine, 5-amino-4-chloro-2-methylphenol, 1-naphthol, 1,5-dihydroxy-naphthalene, 1,7-dihydroxy-naphthalene, 2,3-dihydroxy-naphthalene, 2,7-dihydroxy-naphthalene, 2-methyl-1-naphthol acetate, 1,3-dihydroxybenzene, 1-chloro-2,4-dihydroxybenzene, 2-chloro-1,3-dihydroxybenzene, 1,2-dichloro-3,5-dihydroxy-4-methylbenzene, 1,5-dichloro-2,4-dihydroxybenzene, 1,3-dihydroxy-2-methylbenzene, 3,4-methylenedioxy-phenol, 3,4-methylenedioxy-aniline, 5-[(2-hydroxyethyl)amino]-1,3-benzodioxol, 6-bromo-1-hydroxy-3,4-methylenedioxy-benzene, 3,4-diamino-benzoic acid, 3,4-dihydro-6-hydroxy-1,4(2H)-benzoxazine, 6-amino-3,4-dihydro-1,4(2H)-benzoxazine, 3-methyl-1-phenyl-5pyrazolone, 5,6-dihydroxy-indole, 5,6-dihydroxy-indoline, 5-hydroxy-indole, 6-hydroxy-indole, 7-hydroxy-indole and 2,3-indolinedione come into consideration.
Although the advantageous properties of the compounds of formula (I) described here suggest that these be used as the only developer, it is, of course, also possible to use these compounds together with known developers, such as 1,4-diaminobenzene, 2,5-diaminotoluene, 2,5-diaminophenylethanol, 4-aminophenol and its derivatives (for example, 4-amino-3-methylphenol), 4,5-diamino-1-benzyl-1H-pyrazole, 4,5-diamino-1-((4xe2x80x2-methylbenzyl)-1H-pyrazole, 4,5-diamino-1H-pyrazole, 4,5-diamino-1-(4xe2x80x2-methoxybenzyl)-1H-pyrazole, 4,5-diamino-1-(3xe2x80x2-methoxybenzyl)-1H-pyrazole, 4,5-diamino-1-(4xe2x80x2-chlorobenzyl)-1H-pyrazole, 4,5-diamino-1-((4xe2x80x2-methylphenyl)-1H-pyrazole, 4,5-diamino-1-(4xe2x80x2-methoxyphenyl)-1H-pyrazole, 4,5-diamino-1-(3xe2x80x2-methoxyphenyl)-1H-pyrazole, 4,5-diamino-1-(4xe2x80x2-chlorophenyl)-1H-pyrazole, 4,5-diamino-1-(2xe2x80x2-hydroxyethyl)-1H-pyrazole, 4,5-diamino-1-methyl-1H-pyrazole, 4,5-diamino-1-ethyl-1H-pyrazole, 4-amino-1-((4-methoxyphenyl)methyl)-5-(methylamino)-1H-pyrazole, 4-amino-5-((2-hydroxyethyl)amino)-1-(phenylmethyl)-1H-pyrazole, 4,5-diamino-1-methyl-3-phenyl-1H-pyrazole, 4,5-diamino-1-(2-hydroxyethyl)-3-phenyl-1H-pyrazole, 4,5-diamino-1,3-dimethyl-1H-pyrazole, 4,5-diamino-3-methyl-1-phenyl-1H-pyrazole, 4,5-diamino-1-(1-isopropyl)-1H-pyrazole or tetraaminopyrimidines.
The couplers and the developers may be contained in the inventive dyes in each case individually or in admixture with one another, the total amount of the couplers and the developers in the inventive dye (based on the total amount of the dye) in each case being about 0.005 to 20 percent by weight, preferably about 0.01 to 5.0 percent by weight and particularly 0.1 to 2.5 percent by weight. The total amount of the combination of developer and coupler in the dye described here preferably is about 0.01 to 20 percent by weight, an amount of about 0.02 to 6 percent by weight and especially of 0.2 to 10 percent by weight being particularly preferred. The developers and couplers generally are used in approximately equimolar amounts; in this connection, however, it is not disadvantageous if the developers or the couplers are present in a certain excess (such as a ratio of coupler to developer of 1:2 to 1:0.5).
Furthermore, the inventive dye may additionally contain other dye components, such as 6-amino-2-methylphenol and 2-amino-5-methylphenol, as well as conventional direct dyes, for example, triphenylmethane dyes such as 4-[(4xe2x80x2-aminophenyl)-(4xe2x80x2-imino-2xe2x80x3,5xe2x80x3-cyclohexadiene-1xe2x80x3-ylidene)-methyl]-2-methylaminobenzene monohydrochloride (C.I. 42 510) and 4-[(4xe2x80x2-amino-3xe2x80x2-methyl-phenyl)-(4xe2x80x3-imino-3xe2x80x3-methyl-2xe2x80x3,5xe2x80x3-cyclohexadiene-1xe2x80x3-ylidene)-methyl]-2-methylaminobenzene monohydrochloride (C.I. 42 520), aromatic nitro dyes such as 4-(2xe2x80x2-hydroxyethyl)amino-nitrotoluene, 2-amino-4,6-dinitrophenol, 2-amino-5-(2xe2x80x2-hydroxyethyl)amino-nitrobenzene, 2-chloro-6-(ethylamino)-4-nitrophenol, 4-chloro-N-(2-hydroxyethyl)-2-nitroaniline, 5-chloro-2-hydroxy-4-nitroaniline, 2amino-4-chloro-6-nitrophenol and 1-[(2xe2x80x2-ureidoethyl)amino-4-nitrobenzene, azo dyes such as the sodium salt of 6-[(4xe2x80x2-aminophenyl)azo]-5-hydroxy-naphthalene-1-sulfonic acid (C.I. 14 805) and dispersion dyes such as, for example, 1,4-diaminoanthraquinone and 1,4,5,8-tetraaminoanthraquinone. The aforementioned dye components may be contained in the inventive dyes in an amount of about 0.1 to 4 percent by weight.
Of course, if the couplers and developers as well as the other dye components are bases, they may also be used in the form of their physiologically compatible salts with organic or inorganic assets, such as hydrochloric acid or sulfuric acid, or, if they have aromatic OH groups, in the form of the salts with bases, such as alkali phenolates.
Moreover, the inventive dyes, if they are to be used to dye hair, may also contain other additives, conventionally used in cosmetic materials, for example, antioxidants, such as ascorbic acid, thioglycolic acid or sodium sulfite, as well as perfume oils, complexing agents, wetting agents, emulsifiers, thickeners and care materials.
The inventive dyes may be prepared in the form of a solution, especially an aqueous or aqueous alcoholic solution. However, the especially preferred form of the preparation is a cream, a gel or an emulsion. Its composition represents a mixture of the dye components with additives, which are usually employed for such preparations.
Conventional additives for solutions, creams, emulsions or gels are, for example, solvents such as water, low molecular weight aliphatic alcohols, such as ethanol, propanol or isopropanol, glycerin or glycols, such as 1,2-propylene glycol, wetting agents or emulsifiers of the anionic, cationic, amphoteric or nonionic class of surface active substances, such as fatty alcohol sulfates, ethoxylated fatty alcohol sulfates, alkyl sulfonates, alkylbenzene sulfonates, alkyltrimethylammonium salts, alkylbetaines, ethoxylated fatty alcohols, ethoxylated nonylphenoles, fatty acid alkanolamides and ethoxylated fatty acid esters, furthermore, thickeners such as higher molecular weight fatty alcohols, starch, cellulose derivatives, petroleum jelly, paraffin oil and fatty acids, as well as care materials, such as cationic resins, lanolin derivatives, cholesterol, pantothenic acid and betaine. The components mentioned are used in amounts, which a customary for such purposes; for example, the wetting agents and emulsifiers are used in concentrations of about 0.5 to 30 percent by weight, the thickness in an amount of about 0.1 to 25 percent by weight and the care materials in a concentration of about 0.1 to 5 percent by weight.
Depending on the composition, the inventive dye may be slightly acidic, neutral or alkaline. In particular, it has a pH of 6.5 to 11.5, the adjustment to a basic pH preferably being made with ammonia. However, organic amines, such as monoethanolamine and triethanolamine, or also inorganic bases, such as sodium hydroxide and potassium hydroxide may also be used. For adjusting the pH in the acidic range, inorganic organic acids, such as phosphoric acid, acetic acid, citric acid or tartaric acid comes into consideration.
If they are to be used for the oxidative dyeing of hair, the dyes, described above, are mixed immediately before use with an oxidizing agent and an amount of dye, sufficient for the treatment, is applied on the hair. Generally, about 50 to 200 gram of this mixture is applied, depending on the fullness of the latter. The ready-for-use oxidation dye, obtained upon mixing with the oxidizing agent, preferably has a pH of 6.5 to 11.5.
The following come into consideration as oxidizing agents for developing the hair dyeing: mainly hydrogen peroxide or its addition compounds with urea, melamine, sodium borate or sodium carbonate in the form of a 3 percent to 12 percent and preferably a 6 percent aqueous solution, also oxygen from the air. If a 6 percent hydrogen peroxide solution is used as oxidizing agent, the ratio by weight of hair dyeing agent to oxidizing agent is 5:1 to 1:2 and preferably 1:1. Larger amounts of oxidizing agent are used especially for higher concentrations of dye in the hair-dyeing agent or if greater bleaching of the hair is intended at the same time. The mixture is allowed to act on the hair for about 10 to 45 minutes and preferably for 30 minutes at 15xc2x0 to 50xc2x0 C. The hair is then rinsed with water and dried. Optionally, after the rinsing, the hair is washed with a shampoo and possibly rinsed with a weak organic acid, such as citric acid or tartaric acid. Subsequently, the hair is dried.
The inventive dye, containing N-benzyl-p-phenylenediamine derivatives of Formula (I) as developer, makes dyeings possible with excellent color fastness, especially as far as light fastness, wash fastness and crock fastness are concerned. With regard to the color properties, the inventive dyeing agent offers a wide range of different color nuances, ranging from blond, brown, purple and violet to blue and black color shades, depending on the nature and composition of the dye components. The shades of color are distinguished here especially by their color intensity. The very good dyeing properties of the dye of the present invention are furthermore shown by the fact that this material enables even grayish hair, which has not previously been damaged chemically, to be dyed without problems and with good covering power.
The inventive N-benzyl-p-phenylenediamine derivatives of Formula (I) can be synthesized using known methods, such as the methods described in the examples.
The N-benzyl-p-phenylenediamine derivatives of Formula (I) are readily soluble in water and make dyeings possible with a high color intensity and excellent color fastness, especially as far as light fastness, wash fastness and crock fastness are concerned. They furthermore have an excellent shelf life, especially as a component of the oxidation dyes, which are described here.
A further object of the present invention are new N-benzyl-p-phenylenediamine derivatives of Formula (I), in which R4 is not a nitro group, a methyl group, a hydroxy group, an amino group, a dimethylamino group, a bromine atom or a chlorine atom, when R1=R2=R3=R5=hydrogen, or their physiologically compatible, water-soluble salts.
The following examples are intended to explain the object of the invention in greater detail, without limiting the invention to these examples.